Fire-extinguishing apparatus



Aug. 31, 1943. M KEEFE, JR Y 2,328,345

- FIRE-EXTINGUISHING APPARATUS Filed April 17, 1942 INVENTOR ATTORNEYSPatented Aug. 31, 1943 FIRE-EXTINGUISHING APPARATUS Michael E; Keefe,Jr., Jersey City, J., assignor to National Powder ExtinguisherCorporation, Jersey City, N. J., a corporation of Delaware ApplicationApril 17, 1942, Serial No. 439,307

4 Claims. (Cl. 169-31) This invention relates to fire-extinguishingapparatus by means of which a dry fire-extinguishing powder is blownupon the fire by means of an inert gas, such as carbon dioxide. Thepowder iseommonly stored within a cylindrical container and dischargedthrough a nozzle at the lower end by means of gas introduced underpressure. Although the powder -must be free-flowing, and remainfree-flowing even after long storage, it does not possess the fluidityof. a liquid and is subject to arching under pressure. It is, therefore,not possible to expel the powder by pressure applied from above nomatter how great, and the gas must be introduced at different levelsalong the'powder column beginning at a point just back of the nozzlemouth in order to keep the powder mass loose and free from packing andarching. Various means have been proposed for expelling the powder inthis way, but none, so far as I am aware, has been whollysuccessful.

It is the object of my invention to provide a dry powder fireextinguisher capable of expelling the powder in' a free-flowing streamwithout packing or arching and without the use of excessive gaspressures, and generally to improve upon apparatus of this type.

In the accompanying drawing I have illustrated a preferred embodiment ofmy invention. In the drawing Figure l is a vertical section through theapparatus; Figure 2 is a transverse section taken along line 22 ofFigure 1; and Figure 3 is a detail showing a novel closure for thenozzle.

The fire extinguisher illustrated comprises a cylindrical container Ihaving a dome-shaped top 2, a similarly shaped bottom 3 and a taperindischarge nozzle 4, the whole being supported by a depending skirt .5provided around its bottom with an inwardly rolled peripheral edge 6which serves as a convenient and simple hand grip when the extinguisheris in use. The powder is introcal duced into this cylinder through afeed opening 1 in the top 2 defined by an inwardly turned threadedflange 8. This opening is closed by a cap nut 8 making threadedengagement with the fiange'll. I have found that the natural resiliencyoi. the sheet metal of which the top is made, is suflicient to producean air-tight seal with the cap nut without the interposition of agasket.

Spilling of the powder through the discharge end 01' the nozzle when theextinguisher is not in use is prevented by means of a closure llcomprising a rivet head l2, or similar structure, which fits over theend of the nozzle and is normally held in place by means 01' asupporting spring arm l3 pivoted on the skirt at ll, offset verticallyfrom the nozzle.

The gas for expelling the powder is introduced through a verticalone-piece copper tube l5 of uniform diameter parallel to and spaced fromthe container wall and extending from a point adjacent the upper end ofthe cylinder to a point adjacent the lower end. This tube is providedwith four branch tubes l6 which extend laterally from the tube atequally spaced intervals and are normal to a radius passing through thetube IS. The outer ends of these four branch tubes follow substantiallythe curvature of the cylindrical wall of the container, as shown inFigure 2, and turn downwardly as shown in Figure 1. The discharge endsof the four tubes are in vertical alinement. Two other branch tubes I!and I8 extend downwardly from the lower end of the tube l5. These alsoare of reduced diameter. The shorter tube l1 terminates within thedome-shaped bottom 3 Just above the upper end of the nozzle, while thelonger tube l8 extends down within the nozzle and approaches itsdischarge end.

The gas source is a carbon dioxide cylinder l9 lying within acylindrical casing 2| spaced from but connected to the cylindricalcontainer I. The cylinder I 9 is provided with a valve 22, the outletiron which is suitably coupled to the upper end of the tube IS.

The apparatus operates as follows: The valve 22 is opened to permit thecompressed carbon dioxide to enter the tube IS. The diameter of thistube is such that the pressure throughout its length is substantiallyequal. from the tube l5 into the branch tubes l6 and because of theshape of these tubes enters the powder mass tangentially and downwardly.This tends to set up a whirling action within the mass having a downwarddirection. The use of a single piece of copper tubing as a main line ofsubstantial diameter permits expansion of the gas to take placethroughout the required perpendicular dimension of the container. Theeven spacing of the four branch lines permits the gas to be injectedthrough them virtually simultaneously at points within the container sospaced as to compel the whirling motion of the powder to be accomplishedevenly throughout the container. Each of these smaller branch linesbeing of the same length, they terminate in a line parallel to andwithin the container so that the whirling motion begins throughout theentire container at points along a vertical line and at approximatelythe same instant, and continues evenly during the entire period of thedischarge The ,gas passes .of the powder. The discharge ends of thebranch tubes turning downwardly, there is no possibility that the powdermay fall into the tube l B and interfere with the immediate discharge ofgas when the valve 22 is opened. The tube IE is spaced away from theside of the container, thus ofleringlittle, if any, resistance to thewhirling powder within the container. The gas emerging from the branchtube i1 tends to agitate the powder at the base of the container andovercomes any tendency to arch; while the gas passing through the branchtube expels the powder which has reached the nozzle in a continuousstream having a substantial pressure and range. As soon as the increasedgas pressure reaches the discharge end of the nozzle, the closure I l isunseated and immediately drops to one side, as shown in dotted lines inFigure 3 so that it in no way interferes with the discharge of thepowder.

The pressure developed in the container I is normally about 150 poundsper square inch. In order to protect the container, which is made ofrelatively thin metal, in the event of some stoppage I provide a safetyvalve 23 in the upper side Wall of the container.

I claim:

1. Fire-extinguishing apparatus of the dry powder type comprising acylindrical container for the powder, a discharge nozzle at the lowerendof the cylindrical container, a vertical tube of uniform diameterextending from a point within the container near the top to a pointneanjthe nozzle, branch tubes of smaller diameter extending laterallyfrom the tube at spaced intervals, the outer ends of the branch tubesfollowing generally the curvature of the cylindrical wallwithin thecontainer near thetop to a point near the nozzle, branch tubes ofsmaller diameter extending laterally from the tube at equally spacedintervals, the .outer ends of the tubes turning downward and followinggenerally the curvature of the cylindrical wall of the container andterminating one above the other in a vertical line, other branch tubesextending downwardly from the end of the tube toward the nozzle, andmeans for introducing gas under pressure into the tube.

- 3. Fire-extinguishing apparatus of the dry powder type comprising acylindrical container for the powder, a discharge nozzle at the lowerend of the cylindrical container, a vertical tube of uniform diameterextending from a point near the top of the container to a point near thenozzle and spaced from the cylindrical wall of the container, tubes ofsmaller diameter branching laterally from the vertical tube at spacedintervals normal to the radius of the cylinder passing through the tube,extending close to the cylindrical wall of the container, and bendingdownwardly while following substantially the curvapressure into thetube.

ture of the wall, other branch tubes extending downwardly from the endof the vertical tube toward the nozzle, and means for introducing gasunder pressure into the tube.

4. Fire-extinguishing apparatus of the drypowder type comprising acylindrical container for the powder, a discharge nozzle at the lowerend of the cylindrical container, a vertical tube MICHAEL E. JR.

